Heredity: Our Genetic Background

Ch. 3.4

Heredity is the transmission of characteristics from parents to offspring.

Psychologists study heredity to determine why people behave as they do.

Heredity transmits: Physical traits: hair

color, eye color. Psychological traits:

shyness, leadership, ability, aggressiveness.

Ex.: U.S. serviceman captured in Korean War by Chinese. Profiling.

Other: anxiety, depression, bipolar disorder, alcoholism.

Traditional Korean Medical Typology

Genes and Chromosomes

Genes are the basic building blocks of heredity.

Traits are determined by pairs of genes, with one gene in each pair inherited from each parent.

Genes are found in threadlike structures called chromosomes.

46 chromosomes=23 pairs

1 from father 1 from mother

Nature vs. Nurture

Nature=what we inherit-(people are the way they are because of biological makings.

Nurture=environmental factors-family, education, culture, living conditions.

Today, most psychologists believe that both determine our psychological makeup.

Kinship Studies

Twins: Identical twins=100% of genes

Fraternal twins=50% of genes

Shared traits: intelligence, traditionalism, risk avoidance, aggression, leadership

Twins reared apart even share same mannerisms.

19th & 20th Century Heredity Propaganda